The present invention relates to the general technical field of surgical pins for holding together and aligning two pieces of bone, in particular finger or toe phalanges, the two pieces of bone being held together by being put into contact with each other.
The present invention provides a surgical device for holding together and aligning at least two pieces of bone, the device comprising:
a surgical pin suitable for being implanted axially in the pieces of bone to be held together; and
a protective plug provided with a through channel for enabling it to be engaged on the pin, said plug including a locking orifice in which locking means can be inserted to lock the plug in position relative to the pin.
In various surgical situations, for example with bone deformations or fractures in the phalanges of the foot or the hand, it is necessary to cause the phalanges of the foot or the hand to be held together.
In general, surgeons then make use of external mechanical elements designed, over a determined length of time, to hold together and keep in place bone fractions so as to allow osteosynthesis to take place.
Thus, it is already known that use can be made of compression clips. However they are not in general use and they suffer from various drawbacks associated in particular with the pieces of bone for holding together often not being held sufficiently stably. Compression clips also suffer from a drawback associated with the difficulty of putting them in place, with it often being extremely difficult to find a particular axial direction and then to maintain it.
That is why it is often preferred to use techniques that involve inserting a surgical pin through the skin, with the pin being engaged axially through the pieces of bone that are to be held together.
Recourse to metal pins passing through all or part of two pieces of bone to be held together naturally presents the advantage of enabling the pieces of bone to be held on an axial direction that is particularly well aligned. In general, such a pin is put into place with the help of a motor to facilitate causing the free end of the pin to penetrate into the bone, while the non-penetrating free end is then necessarily present at the percutaneous level of the foot or the hand. This free end can present a certain amount of danger and consequently it is generally curved by the surgeon.
In order to reduce the risk of catching or injury, metal or plastic protection pieces also exist that form a kind of plug which is threaded onto the pin from the free end via a through channel formed in the mass of the plug.
Presently-known devices of that type comprise a spherical protective plug pierced along an axis of symmetry by a channel of cylindrical section. Such a known device is also provided with a tapped locking orifice opening out into the through channel and extending along a direction that is substantially orthogonal thereto. The locking orifice contains a grub screw that can be moved to constitute means for locking the plug and the pin in some relative position. Once the pin is in place and the plug has been engaged using its through channel, the plug can be locked in position by the lock screw, which, on being tightened, presses against the pin where the through channel intersects the locking orifice.
Consequently, that device provides a degree of protection for the free end of the pin and avoids the patient being injured or catching on various obstacles in the course of daily life. Once bone fusion has been achieved, the surgeon then removes the pin making use of pliers that enable the pin to be twisted and extracted axially so that it can slide. Although presently-known devices make a positive contribution to protecting the end of the pin, they are relatively ineffective when it comes to the handling required for extracting the pin, which means that it is necessary to make use of an additional tool for providing assistance in extraction.
Such a known device naturally provides a positive contribution to protecting patients, but it nevertheless suffers from various drawbacks, and in particular the need to use an inside thread in the locking orifice. This is difficult to provide on elements that are as small as the protective plugs used, so the threading operation is difficult to achieve industrially. Furthermore, such an operation gives rise to non-negligible additional expense, particularly since such an operation can be performed only by using high precision equipment that is correspondingly expensive.
Furthermore, making such a device turns out to give rise to additional problems with unmolding of the parts and that has led to the use of such known devices being somewhat limited.
Consequently, the objects given to the invention lie in finding a remedy to the various drawbacks mentioned above and in proposing a novel surgical device for holding pieces of bone together and aligning them, and in particular for the phalanges of the foot or the hand, such a device being particularly simple to make and to use, and in particular being easy to extract, while nevertheless being low in cost.
Another object of the invention seeks to propose a novel surgical device that reduces the risks of catching or of injury to the patient.
Another object of the invention seeks to propose a novel surgical device making it particularly simple and reliable to lock a protective plug into place on a surgical pin.
Another object of the invention seeks to propose a novel surgical device enabling a common size of plug to be fitted to surgical pins of various diameters.
Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled into the art.
These objects of the invention are achieved by means of a surgical device for holding together and aligning at least two pieces of bone, the device comprising:
a surgical pin suitable for being implanted axially in the pieces of bone to be held together; and
a protective plug provided with a through channel for enabling it to be engaged on the pin, said plug including a locking orifice in which locking means can be inserted to lock the plug in position relative to the pin;
wherein:
the locking orifice is made in such a manner as to open out substantially tangentially into the through channel so as to form a surface S; and
the locking means presents a matching cross-section such that on being inserted into the locking orifice it can lock the plug relative to the pin by compressive/locking contact via the surface S.